Smart alternator or stupid one ?

[roadwarrior]

Having just bought a autosleeper winchcombe with a lazy cab aircon, (blower loses power after an hour, but picks back up if you turn off aircon for a few mins and turn on aircon again ... I had thought the alternator was at fault and had another fitted. NOW - They have fitted a smart alternator, and of course it's not charging the auxiliary battery, but I didn't notice as a few days later I set off for France (still there)
My question is this ? Do I go back and say oy you fitted the wrong type of alternator or not ? I accept the smart one is supposed to be better but it will I actually get better fuel consumption for all my wallet efforts? I know I would have to buy a battery to battery charger which included my solar panel charging and that's a few more hundred quid and I still have to fix the blower problem. Also a little confused about smart alternators buggering up some battery types as I read that some can't take the higher voltage it puts out in bursts. Gentlemen ?

 

[roadwarrior]

Yes the fuse seems to be ok, is it the em45 that deals with split charging then ?
Noting what you say about the volts dropping the fan rate has a ring of truth about it but sounds a bit shit to me if have to cook in the cab to make an environmentalists wet dream come true.

While I'm thinking about it, does anybody know if the small twin 12v aux batteries I have found under the passenger seat is standard ?

 

[GeoffnDee]

If you have a smart alternator fitted , as far as I know , a different method of charging the leisure battery is used (not a split charge relay) but I had hoped a blown fuse, if there was one, in a EM50/EM45 may have been linked to the reason that your leisure battery is not being charged by whatever is used with smart alternator charging of the starter/leisure batteries. (B2B ? )
The fridge 12v operation when driving may well be controlled through the Sargent EM45 .

 

[Captain Birdseye]

Having just bought a autosleeper winchcombe with a lazy cab aircon, (blower loses power after an hour, but picks back up if you turn off aircon for a few mins and turn on aircon again ... I had thought the alternator was at fault and had another fitted. NOW - They have fitted a smart alternator, and of course it's not charging the auxiliary battery, but I didn't notice as a few days later I set off for France (still there)
My question is this ? Do I go back and say oy you fitted the wrong type of alternator or not ? I accept the smart one is supposed to be better but it will I actually get better fuel consumption for all my wallet efforts? I know I would have to buy a battery to battery charger which included my solar panel charging and that's a few more hundred quid and I still have to fix the blower problem. Also a little confused about smart alternators buggering up some battery types as I read that some can't take the higher voltage it puts out in bursts. Gentlemen ?

We have one as standard equipment and I wish we didn't.

 

[MGSMerc.]

I had a similar problem on the Sprinter engine and found that the cure in my case was to wire the B2B direct to the battery terminal. For some reason the various fuses on the top of the battery had either blown or had a timer attached and switching them off. Very confusing.

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[roadwarrior]

Yes and I changed it just in case.

 

[roadwarrior]

I don't have the tools to get the seat off to look at the the two batteries till I get home next week but I hope to get know more then

 

[roadwarrior]

If you have a smart alternator fitted , as far as I know , a different method of charging the leisure battery is used (not a split charge relay) but I had hoped a blown fuse, if there was one, in a EM50/EM45 may have been linked to the reason that your leisure battery is not being charged by whatever is used with smart alternator charging of the starter/leisure batteries. (B2B ? )
The fridge 12v operation when driving may well be controlled through the Sargent EM45 .

Yes I saw a fuse for the fridge and it's working perfectly

 

[Pausim]

If you have a smart alternator fitted , as far as I know , a different method of charging the leisure battery is used (not a split charge relay)

I think that statement needs qualifying with “should have a different method of charging”. Some converters have been a bit slow in changing over to smart alternator changing arrangements.

 

[roadwarrior]

I removed the passenger seat and found these two 100 amp batteries that dont look too old but as you can see there is a trailor relay thingy which I'm unsure about. Running the engine it got a 14 volt charge across both the batteries upon start up but I have no way of testing the batteries. But. I do know every day after a days driving I would only have about 12.5 at the aux batteries and any use quickly dropped the voltage.

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[Lenny HB]

The trailer box is for towbar electrics.

Just read through this thread again, my thoughts are yes you have a smart alternator but you do not have a B2B, so your leisure batteries are never going to get a proper charge.

With some manufacturers the B2B is an option & if it wasn't specified the batteries are never going to charge.

 

[Pausim]

The trailer box is for towbar electrics.

Just read through this thread again, my thoughts are yes you have a smart alternator but you do not have a B2B, so your leisure batteries are never going to get a proper charge.

With some manufacturers the B2B is an option & if it wasn't specified the batteries are never going to charge.

I agree. With a smart alternator and a basic split charge relay the the ecu (alternator) could be seeing the 2 leisure batteries and the 1 engine battery as a single unit. If so it will not only fail to charge the leisure batteries but will draw on them until it has reduced their voltage to the level it wants to keep the engine battery at i.e. 12.5V

 

[autorouter]

Have you checked that fuse in the battery positive link wire? If that's blown you're only using one of the batteries.

It's easy to tell whether you have a B2B or not if you can take a few voltage readings.

First measure the voltages of the batteries with no EHU and solar, with the engine stopped.

Then start the engine, and check the voltages. The starter battery voltage may or may not rise, depending on how the smart alternator is feeling. If the leisure battery voltage is always the same as the starter battery voltage when the engine is running, then you don't have a B2B, it's a split charge relay. If the leisure battery voltage rises to be about 14.5V, but the starter battery voltage doesn't then you have a B2B.

It's possible that by coincidence the voltage of both batteries will be about 14.5V even if there is a B2B fitted. The point is, with a split charge relay the voltages are always the same. But with a B2B the leisure battery goes up to about 14.5V, then down to about 13.5V when it's full. The starter battery will be all over the place, from 12.5V to 14.5V depending on what the smart alternator thinks.

 

[Lenny HB]

It's possible that by coincidence the voltage of both batteries will be about 14.5V even if there is a B2B fitted. The point is, with a split charge relay the voltages are always the same. But with a B2B the leisure battery goes up to about 14.5V, then down to about 13.5V when it's full. The starter battery will be all over the place, from 12.5V to 14.5V depending on what the smart alternator thinks.

But won't the B2B put a load on the starter battery making the alternator kick into charge mode.

 

[roadwarrior]

I agree it's a trailer box but what is it doing on the aux batteries? I would have thought any towing boxes would be on the van battery not an aux battery.

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[Reallyretired]

I have a stupid alternator and it charges the leisure battery fine. I don't know what difference a smart one would make to fuel economy but I doubt it would make up for the cost of all the adaptations that would need to be made if a smart one was fitted.
I would revert to the correct alternator rather than have a load of expense and possible grief.

 

[rod_vw]

I agree it's a trailer box but what is it doing on the aux batteries? I would have thought any towing boxes would be on the van battery not an aux battery.

There is no reason to believe that the trailer unit is drawing any current from the leisure batteries, it's just been located there for ease of fitting I would guess. You can see from the terminal designations 30 = ignition switched +12v -- 31 = Chassis -ve . The other connections are rear lights etc plus a CAN Bus link to control the disabling of rear sensors, rear fog light(s) etc. on the towing vehicle.

 

[GeoffnDee]

It could be worth checking the connections on the rear of the EM45 unit as the starter battery has connections there along the low D+ signal to the PSU (through a poly-fuse)

 

[roadwarrior]

is it normal for 0.6 amp drain on aux batteries with nothing on except the panel im reading it from ?
I'm pretty sure my leasure batteries are nackered having seen them down to 11.4 off grid with a tiny load ( charging a phone overnight) so what kind do i get to replace them, heard so many stories about lithium vs agm vs wet cell i dont know what to think -